Thinking of fitting 275/40/19 tires in place of 285/45/19, would there be much of a difference?

I drive an SUV that has 285/45/19 Bridgestone Dueler's at the rear, these are the OEM tires. Unfortunately, they're about $275 per tire and only last me about 15,000 miles. The only viable alternative for this size is a Pirelli tire which is equally as expensive and probably will last the same length of time.In places of these tires I'm thinking of putting on Michelin 275/40/19 tires because my dad can get them for about $75 per tire, (they're lightly used). So that's $150 versus about $550 for the OEM tires.Wondering if their will be any substantial difference by switching to a slightly different size or any reason for concern? Thanks. via /r/cars http://ift.tt/2t0z4Gn